Narrator: That January, with the backing of Eisenhower, Spaatz revived Operation Thunderclap, the all-out assault on German morale he had once vehemently opposed. This time it would include attacks on transportation hubs in Leipzig and Dresden, to put pressure on German defenses on the Russian front. But the centerpiece of the operation, reversing years of American strategic policy, would be a massive air assault on Berlin.

Tami Davis Biddle, Historian: Doolittle is told that he will bomb the city of Berlin. This is different language. He’s very uncomfortable with it. He’s not comfortable with designating an entire city as a target. He protests to Spaatz and he says, “This is not what we do. We attack specific locations within cities. We may attack cities, but we’re looking for marshalling yards, we’re looking for factories, we’re looking for specific sites within those.”

Conrad Crane, Historian: And Spaatz says, “No. For this raid we have to bomb the- we’re bombing the center of the city. This is an attack on the center of Berlin.”

Narrator: Doolittle sent a hard-edged memo to his commanding officer. The Berlin attack, he wrote Spaatz, would “violate the basic American principle of precision bombing of targets of strictly military significance.” Spaatz was unmoved. Operation Thunderclap — the all out attack on Berlin — would proceed as planned.

Conrad Crane, Historian: The Thunderclap raid is important in that it can clearly identify where the American Air Force says, “Yeah, we’re going to destroy a city.” And that’s one of the things that made Doolittle so disturbed about it, because he says, 'We’re really moving completely away from everything that makes us different, makes us unique, makes us more humane.” But he did it. He followed his orders and he did it. And you can argue that once you’ve done that once, it makes it easier to do again.

Narrator: On February 3rd 1945, 1,003 bomber crews were briefed for the largest American air mission of the war: an attack on Berlin — a city of nearly four million people. Sam Halpert was a navigator with the 91st bomber group.

Sam Halpert, Navigator, 8th Air Force: We were briefed to go to Berlin. The map of northern Europe was up there, and there was a ribbon going across, which was our route.

Narrator: Although the target designated by Spaatz was the city of Berlin, Doolittle did his best to give the crews aiming points with clear military value: train stations, marshalling yards, and Goering’s air ministry, just 500 meters from Hitler’s fortified bunker. The bombers, and their escorts, headed east.

The 8th AF had a schizophrenic attitude to bombing civilians. At first they pledged to attack "precision" targets only. As soon as they got their first blind bombing radars in autumn 1943 they began area bombing German cities. After a while they stopped defining their area attacks as such, and instead called them attacks on "marshalling yards". The practice was still the same, though, dropping large percentages of incendiaries on German cities using radar bombing that was known to be very inaccurate.